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cpus: Initialize pseudo-random seeds for all guest cpus

When the -seed option is given, call qemu_guest_random_seed_main,
putting the subsystem into deterministic mode.  Pass derived seeds
to each cpu created; which is a no-op unless the subsystem is in
deterministic mode.

Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
tags/v4.1.0-rc0
Richard Henderson 6 months ago
parent
commit
9c09a2518e
4 changed files with 24 additions and 0 deletions
  1. 9
    0
      cpus.c
  2. 1
    0
      include/qom/cpu.h
  3. 10
    0
      qemu-options.hx
  4. 4
    0
      vl.c

+ 9
- 0
cpus.c View File

@@ -50,6 +50,7 @@
#include "qemu/option.h"
#include "qemu/bitmap.h"
#include "qemu/seqlock.h"
#include "qemu/guest-random.h"
#include "tcg.h"
#include "hw/nmi.h"
#include "sysemu/replay.h"
@@ -1276,6 +1277,7 @@ static void *qemu_kvm_cpu_thread_fn(void *arg)
/* signal CPU creation */
cpu->created = true;
qemu_cond_signal(&qemu_cpu_cond);
qemu_guest_random_seed_thread_part2(cpu->random_seed);

do {
if (cpu_can_run(cpu)) {
@@ -1319,6 +1321,7 @@ static void *qemu_dummy_cpu_thread_fn(void *arg)
/* signal CPU creation */
cpu->created = true;
qemu_cond_signal(&qemu_cpu_cond);
qemu_guest_random_seed_thread_part2(cpu->random_seed);

do {
qemu_mutex_unlock_iothread();
@@ -1478,6 +1481,7 @@ static void *qemu_tcg_rr_cpu_thread_fn(void *arg)
cpu->created = true;
cpu->can_do_io = 1;
qemu_cond_signal(&qemu_cpu_cond);
qemu_guest_random_seed_thread_part2(cpu->random_seed);

/* wait for initial kick-off after machine start */
while (first_cpu->stopped) {
@@ -1592,6 +1596,7 @@ static void *qemu_hax_cpu_thread_fn(void *arg)

hax_init_vcpu(cpu);
qemu_cond_signal(&qemu_cpu_cond);
qemu_guest_random_seed_thread_part2(cpu->random_seed);

do {
if (cpu_can_run(cpu)) {
@@ -1631,6 +1636,7 @@ static void *qemu_hvf_cpu_thread_fn(void *arg)
/* signal CPU creation */
cpu->created = true;
qemu_cond_signal(&qemu_cpu_cond);
qemu_guest_random_seed_thread_part2(cpu->random_seed);

do {
if (cpu_can_run(cpu)) {
@@ -1671,6 +1677,7 @@ static void *qemu_whpx_cpu_thread_fn(void *arg)
/* signal CPU creation */
cpu->created = true;
qemu_cond_signal(&qemu_cpu_cond);
qemu_guest_random_seed_thread_part2(cpu->random_seed);

do {
if (cpu_can_run(cpu)) {
@@ -1724,6 +1731,7 @@ static void *qemu_tcg_cpu_thread_fn(void *arg)
cpu->can_do_io = 1;
current_cpu = cpu;
qemu_cond_signal(&qemu_cpu_cond);
qemu_guest_random_seed_thread_part2(cpu->random_seed);

/* process any pending work */
cpu->exit_request = 1;
@@ -2071,6 +2079,7 @@ void qemu_init_vcpu(CPUState *cpu)
cpu->nr_cores = smp_cores;
cpu->nr_threads = smp_threads;
cpu->stopped = true;
cpu->random_seed = qemu_guest_random_seed_thread_part1();

if (!cpu->as) {
/* If the target cpu hasn't set up any address spaces itself,

+ 1
- 0
include/qom/cpu.h View File

@@ -375,6 +375,7 @@ struct CPUState {
int singlestep_enabled;
int64_t icount_budget;
int64_t icount_extra;
uint64_t random_seed;
sigjmp_buf jmp_env;

QemuMutex work_mutex;

+ 10
- 0
qemu-options.hx View File

@@ -3641,6 +3641,16 @@ the 0x200 sized block starting at 0xffffffc000080000 and another 0x1000 sized
block starting at 0xffffffc00005f000.
ETEXI

DEF("seed", HAS_ARG, QEMU_OPTION_seed, \
"-seed number seed the pseudo-random number generator\n",
QEMU_ARCH_ALL)
STEXI
@item -seed @var{number}
@findex -seed
Force the guest to use a deterministic pseudo-random number generator, seeded
with @var{number}. This does not affect crypto routines within the host.
ETEXI

DEF("L", HAS_ARG, QEMU_OPTION_L, \
"-L path set the directory for the BIOS, VGA BIOS and keymaps\n",
QEMU_ARCH_ALL)

+ 4
- 0
vl.c View File

@@ -128,6 +128,7 @@ int main(int argc, char **argv)
#include "qapi/qapi-commands-ui.h"
#include "qapi/qmp/qerror.h"
#include "sysemu/iothread.h"
#include "qemu/guest-random.h"

#define MAX_VIRTIO_CONSOLES 1

@@ -3349,6 +3350,9 @@ int main(int argc, char **argv, char **envp)
case QEMU_OPTION_DFILTER:
qemu_set_dfilter_ranges(optarg, &error_fatal);
break;
case QEMU_OPTION_seed:
qemu_guest_random_seed_main(optarg, &error_fatal);
break;
case QEMU_OPTION_s:
add_device_config(DEV_GDB, "tcp::" DEFAULT_GDBSTUB_PORT);
break;

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